A wheelchair is a chair mounted on wheels and is used to provide mobility for physically challenged users. A standard wheelchair consists of a seat and back carried by a chassis fitted with two small front wheels, two large rear wheels, and a footrest. The wide variety of wheelchairs currently available are typically variations on the standard wheelchair and are often configured with customized accessories for satisfying specific needs.
Manual or self-propelled wheelchairs are propelled by the occupant, usually through the application of force applied by hand to circular handrims attached to the large, rear wheels. The handrims are located on the outside of the rear wheels, and normally have a diameter slightly less than that of the rear wheels. Powered wheelchairs incorporate motor-powered drive assemblies used to drive the rear and/or front wheels, and are controlled with a joystick or other control device.
As is well known, many thousands of people are confined to wheelchairs each year, due to illness or accident or other misfortune. People who are confined to wheelchairs have either limited or no mobility in their legs, and, in some instances, limited or no mobility in their arms, particularly among those who are partially or completely paralyzed or who have suffered debilitating injury to their arms. Those confined to wheelchairs and who have either partial or complete use of their arms often prefer manual or self-propelled wheelchairs because they require use of their arms to propel the wheelchair. Propelling a wheelchair with the arms has numerous health and mental benefits. Propelling a wheelchair with the arms strengthens the muscles of the arms and can provide cardiovascular benefits as well for those who use their wheelchairs in sports and sport-related activities and long-distance wheelchair training and racing. Because having to use a wheelchair takes away a measure of personal independence, maneuvering a wheelchair manually provides a corresponding measure of independence and control in an otherwise difficult situation, which can increase confidence, personal awareness, and self-image.
In an effort to increase the usefulness of manual or self-propelled wheelchairs, skilled artisans have developed specialized wheelchair attachments for manually propelling wheelchairs that are activated with the use of levers operatively coupled to the rear wheels. The levers are taken up by hand and moved back and forth with the arms, which, in turn, imparts rotation to the rear wheels thereby propelling the wheelchair. Use of such lever-operated wheelchairs serves to strengthen the muscles of the arms and hands, and can provide cardiovascular benefits when used in sports and sport-related activities and long-distance wheelchair training and racing. Furthermore, lever-operated wheelchairs are often capable of achieving higher rates of speed as compared to standard wheelchairs.
Although the advent of lever-operated wheelchairs represents a significant advancement in the art of wheelchairs, none have been entirely satisfactory. For instance, existing lever-operated wheelchairs are difficult to construct, expensive, structurally complicated, difficult to repair, and are unreliable and prone to breakage. Given these and other deficiencies in the art, those having regard for the art will readily appreciate that continued improvement in the field of self-propelled wheelchairs is needed.